Meaning of "Warning: /PLOAD/PBLAST, R/W**(1/3) > 400.0 mus/g**(1/3)"?

Ingeniorator
Ingeniorator New Altair Community Member
edited June 2022 in Community Q&A

Hello everyone,

I'm playing with the PBLAST load in RADIOSS, but the model displays the warning "/PLOAD/PBLAST, R/W**(1/3) > 400.0 mus/g**(1/3)", then lists the affected segment nodes. The solver does not throw an error and wrote the first animation file, but nothing further seems to happen apart from listing every single affected segment node. What exactly is this warning telling me? I defined a 1kg TNT charge near a shell mesh, and the affected surfaces is defined via a surface segment. Searching the documentation did not yield any results, as there seems to be very little about blast loads in there.

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Answers

  • Rogerio Nakano_21179
    Rogerio Nakano_21179 New Altair Community Member
    edited May 2022 Answer ✓

     

    Hi 

    Please verify the comment 3. in the /PLOAD/PBLAST documentation.

    https://2021.help.altair.com/2021.2/hwsolvers/rad/topics/solvers/rad/pblast_starter.htm?zoom_highlight=*pblast

     

    and if you are using consistent unit system, and it is being reflected in the /BEGIN card.

    The PBLAST method relies in the /BEGIN system (input and work)  to correctly convert the test data, that it is based on, in the units you may be consistently using in the modeling.

     

    Hope this is helpful

    Regards

     

  • Ingeniorator
    Ingeniorator New Altair Community Member
    edited May 2022

     

    Hi 

    Please verify the comment 3. in the /PLOAD/PBLAST documentation.

    https://2021.help.altair.com/2021.2/hwsolvers/rad/topics/solvers/rad/pblast_starter.htm?zoom_highlight=*pblast

     

    and if you are using consistent unit system, and it is being reflected in the /BEGIN card.

    The PBLAST method relies in the /BEGIN system (input and work)  to correctly convert the test data, that it is based on, in the units you may be consistently using in the modeling.

     

    Hope this is helpful

    Regards

     

    Hi Rogerio, indeed that was the issue. It stemmed from the fact that I adapted an existing model with a different unit system defined in the /BEGIN card, and altering that solved it. Thank you very much. However, I'd love to know what exactly the warning message is telling and that it's caused by. It still comes up in later stages of a model that uses consistently defined units. Is this due to a larger than expected TNT mass causing a very high amplitude pressure wave?

  • PaulAltair
    PaulAltair
    Altair Employee
    edited May 2022

    Hi Rogerio, indeed that was the issue. It stemmed from the fact that I adapted an existing model with a different unit system defined in the /BEGIN card, and altering that solved it. Thank you very much. However, I'd love to know what exactly the warning message is telling and that it's caused by. It still comes up in later stages of a model that uses consistently defined units. Is this due to a larger than expected TNT mass causing a very high amplitude pressure wave?

    Can you share one of your models that gives the warning?

  • Ingeniorator
    Ingeniorator New Altair Community Member
    edited June 2022

    Can you share one of your models that gives the warning?

    Hello Paul, here's a model showing the above-mentioned warning message. I believe its occurrence is dependent on the TNT mass and the proximity of the detonation center to the part in question, which would be consistent with the mentioning of R and W in the warning message. Interestingly, this model gives a different message to the one mentioned in the title:

    Warning: /LOAD/PBLAST, R/W**(1/3) < 0.5   mus/g**(1/3)

    Is it some sort of stability criterion that must be met?

  • Ingeniorator
    Ingeniorator New Altair Community Member
    edited June 2022

    Can you share one of your models that gives the warning?

    I received an answer from Rogerio stating the following:

    It means the "Scaled Distance Z= R/W**(1/3)" is out of the TM 5-1300 experimental data range and the load fitting can't be done correctly.